A PET scan requires a small amount of radioactive material (tracer). This tracer is given through a vein (IV), usually on the inside of your elbow. Or you breathe in the radioactive material as a gas.
The tracer travels through your blood and collects in organs and tissues. The tracer helps the doctor see certain areas or diseases more clearly.
You wait nearby as the tracer is absorbed by your body. This usually takes about 1 hour.
Then, you lie on a narrow table, which slides into a large tunnel-shaped scanner. The PET scanner detects signals from the tracer. A computer changes the results into 3-D pictures. The images are displayed on a monitor for the doctor to read.
You must lie still during test so that the machine can produce clear images of your brain. You may be asked to read or name letters if your memory is being tested.
The test takes between 30 minutes and 2 hours.